I have received bad certified checks from buyers in the past. Like Bjuice said, if you don't have good solid info on the guy the possibility of getting burned is out there.
Things I would want from him are Full name
Address
City, State & zip
Copy of Driver Liscense
Work Number & Position
I would also need a copy of the cashiers check or USPS money order to be faxed to me for bank verification prior to shipping goods.
JMO
Good Luck